[clang-format] Parse Verilog if statements

[sstwcw]

Summary

This patch mainly handles treating begin as block openers.

While and for statements will be handled in another patch.

[sstwcw]

clang/lib/Format/FormatToken.h

1122

Does anyone know why this part gets aligned unlike the two lists above?

[HazardyKnusperkeks]

clang/lib/Format/FormatToken.h

373

Can't we do that with a type?

I'm not very happy about the alias, because you can still call Tok.getKind().

1122

Have you reformatted the other lines with the same config and revision?
If yes, my guess would be the missing comment.

1499

So you have a blacklist what is not a keyword? Seems a bit non future proof, new C++ keywords would have to be added here.

1561

For consistency reasons add the comment like above.

[sstwcw]

clang/lib/Format/FormatToken.h

373

The main problem I seek to solve with the alias thing is with tok::hash. In Verilog they use a backtick instead of a hash. At first I modified all places in the code to recognize the backtick. MyDeveloperDay said "year really not nice.. its like we can never use tok::hash again!" Using a type also requires modifying all instances of tok::hash if I get you right. How do I please everyone?

1122

It was the missing comment.

1499

This is a whitelist of what is a keyword.

[sstwcw]

add comment

[HazardyKnusperkeks]

clang/lib/Format/FormatToken.h

373

Then you must hide Tok in the private part, so that no one can ever access Tok.getKind() accidentally.

1499

My bad. Go on.

[sstwcw]

abandon alias

[sstwcw]

clang/lib/Format/FormatToken.h

373

In the new version the type of Tok itself gets changed instead. So an alias is not needed.

[HazardyKnusperkeks]

clang/lib/Format/FormatToken.h

1549

Shouldn't we add TT_MacroBlockBegin?

[MyDeveloperDay]

As first passes for adding a new language I think this looks pretty good.

`if (Keywords.isBlockBegin(*FormatTok, Style)) {`

I'm not a massive fan of handling l_brace and begin and end as the same thing, I might be tempted to handle them separately, as then its clear what is happening, but I don't think I'd block it for that.

[sstwcw]

add MacroBlockBegin

[sstwcw]

use isVerilog

[sstwcw]

• add brace

[owenpan]

clang/docs/ClangFormatStyleOptions.rst was out of sync because dump_format_style.py had not been run. Fixed in cc55d97.

[owenpan]

clang/lib/Format/UnwrappedLineParser.cpp

2592

This is likely the culprit of https://github.com/llvm/llvm-project/issues/57509. @sstwcw can you have a look?

[owenpan]

clang/lib/Format/FormatToken.h

1550

Due of what isBlockBegin() is replacing in this patch, TT_MacroBlockBegin should be added in a separate patch (if it's correct to add it) along with corresponding unit tests.

[owenpan]

clang/lib/Format/UnwrappedLineParser.cpp

2592

My bad, but see https://reviews.llvm.org/D123450#inline-1282841.

[owenpan]

In D123450#3465024, @MyDeveloperDay wrote:

`if (Keywords.isBlockBegin(*FormatTok, Style)) {`

I'm not a massive fan of handling l_brace and begin and end as the same thing, I might be tempted to handle them separately, as then its clear what is happening,

+1

[owenpan]

clang/lib/Format/FormatToken.h

1549

Adding TT_MacroBlockBegin here caused an assertion failure. See also D123450#3768367.

clang/docs/ClangFormat.rst

--Wno-error=<value>            - If set don't error out on the specified warning type.
                                        This can be used to enable formatting, even if the
                                        configuration contains unknown (newer) options.
                                        Use with caution, as this might lead to dramatically
                                        differing format depending on an option being
                                        supported or not.
     --assume-filename=<string>     - Override filename used to determine the language.
                                      When reading from stdin, clang-format assumes this
                                      filename to determine the language.
+                                     Unrecognized filenames are treated as C++.
+                                     supported:
+                                       CSharp: .cs
+                                       Java: .java
+                                       JavaScript: .mjs .js .ts
+                                       Json: .json
+                                       Objective-C: .m .mm
+                                       Proto: .proto .protodevel
+                                       TableGen: .td
+                                       TextProto: .textpb .pb.txt .textproto .asciipb
+                                       Verilog: .sv .svh .v .vh
     --cursor=<uint>                - The position of the cursor when invoking
                                      clang-format from an editor integration
     --dry-run                      - If set, do not actually make the formatting changes
     --dump-config                  - Dump configuration options to stdout and exit.
                                      Can be used with -style option.
     --fallback-style=<string>      - The name of the predefined style used as a
                                      fallback in case clang-format is invoked with
                                      -style=file, but can not find the .clang-format

clang/include/clang/Format/Format.h

enum LanguageKind : int8_t {
     LK_ObjC,
     /// Should be used for Protocol Buffers
     /// (https://developers.google.com/protocol-buffers/).
     LK_Proto,
     /// Should be used for TableGen code.
     LK_TableGen,
     /// Should be used for Protocol Buffer messages in text format
     /// (https://developers.google.com/protocol-buffers/).
-    LK_TextProto
+    LK_TextProto,
+    /// Should be used for Verilog and SystemVerilog.
+    /// https://standards.ieee.org/ieee/1800/6700/
+    /// https://sci-hub.st/10.1109/IEEESTD.2018.8299595
+    LK_Verilog
   };
   bool isCpp() const { return Language == LK_Cpp || Language == LK_ObjC; }
   bool isCSharp() const { return Language == LK_CSharp; }
   bool isJson() const { return Language == LK_Json; }
   bool isJavaScript() const { return Language == LK_JavaScript; }
+  bool isVerilog() const { return Language == LK_Verilog; }
 
   /// Language, this format style is targeted at.
   /// \version 3.5
   LanguageKind Language;
 
   /// Indentation logic for lambda bodies.
   enum LambdaBodyIndentationKind : int8_t {
     /// Align lambda body relative to the lambda signature. This is the default.
inline StringRef getLanguageName(FormatStyle::LanguageKind Language) {
   case FormatStyle::LK_Json:
     return "Json";
   case FormatStyle::LK_Proto:
     return "Proto";
   case FormatStyle::LK_TableGen:
     return "TableGen";
   case FormatStyle::LK_TextProto:
     return "TextProto";
+  case FormatStyle::LK_Verilog:
+    return "Verilog";
   default:
     return "Unknown";
   }
 }
 
 } // end namespace format
 } // end namespace clang
 
 namespace std {
 template <>
 struct is_error_code_enum<clang::format::ParseError> : std::true_type {};
 } // namespace std
 
 #endif // LLVM_CLANG_FORMAT_FORMAT_H

clang/lib/Format/Format.cpp

if (FileName.endswith_insensitive(".textpb") ||
     return FormatStyle::LK_TextProto;
   }
   if (FileName.endswith_insensitive(".td"))
     return FormatStyle::LK_TableGen;
   if (FileName.endswith_insensitive(".cs"))
     return FormatStyle::LK_CSharp;
   if (FileName.endswith_insensitive(".json"))
     return FormatStyle::LK_Json;
+  if (FileName.endswith_insensitive(".sv") ||
+      FileName.endswith_insensitive(".svh") ||
+      FileName.endswith_insensitive(".v") ||
+      FileName.endswith_insensitive(".vh")) {
+    return FormatStyle::LK_Verilog;
+  }
   return FormatStyle::LK_Cpp;
 }
 
 FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code) {
   const auto GuessedLanguage = getLanguageByFileName(FileName);
   if (GuessedLanguage == FormatStyle::LK_Cpp) {
     auto Extension = llvm::sys::path::extension(FileName);
     // If there's no file extension (or it's .h), we need to check the contents

clang/lib/Format/FormatToken.h

public:
   void overwriteFixedType(TokenType T) {
     TypeIsFinalized = false;
     setType(T);
   }
   bool isTypeFinalized() const { return TypeIsFinalized; }
 
   /// The number of newlines immediately before the \c Token.
   ///
   /// This can be used to determine what the user wrote in the original code
   /// and thereby e.g. leave an empty line between two function definitions.
   unsigned NewlinesBefore = 0;
 
   /// The offset just past the last '\n' in this token's leading
   /// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
   unsigned LastNewlineOffset = 0;
 
   /// The width of the non-whitespace parts of the token (or its first
AdditionalKeywords(IdentifierTable &IdentTable) {
     kw_uint = &IdentTable.get("uint");
     kw_ulong = &IdentTable.get("ulong");
     kw_unchecked = &IdentTable.get("unchecked");
     kw_unsafe = &IdentTable.get("unsafe");
     kw_ushort = &IdentTable.get("ushort");
     kw_when = &IdentTable.get("when");
     kw_where = &IdentTable.get("where");
 
+    kw_always = &IdentTable.get("always");
+    kw_always_comb = &IdentTable.get("always_comb");
+    kw_always_ff = &IdentTable.get("always_ff");
+    kw_always_latch = &IdentTable.get("always_latch");
+    kw_assign = &IdentTable.get("assign");
+    kw_assume = &IdentTable.get("assume");
+    kw_automatic = &IdentTable.get("automatic");
+    kw_before = &IdentTable.get("before");
+    kw_begin = &IdentTable.get("begin");
+    kw_bins = &IdentTable.get("bins");
+    kw_binsof = &IdentTable.get("binsof");
+    kw_casex = &IdentTable.get("casex");
+    kw_casez = &IdentTable.get("casez");
+    kw_celldefine = &IdentTable.get("celldefine");
+    kw_checker = &IdentTable.get("checker");
+    kw_clocking = &IdentTable.get("clocking");
+    kw_constraint = &IdentTable.get("constraint");
+    kw_cover = &IdentTable.get("cover");
+    kw_covergroup = &IdentTable.get("covergroup");
+    kw_coverpoint = &IdentTable.get("coverpoint");
+    kw_disable = &IdentTable.get("disable");
+    kw_dist = &IdentTable.get("dist");
+    kw_end = &IdentTable.get("end");
+    kw_endcase = &IdentTable.get("endcase");
+    kw_endchecker = &IdentTable.get("endchecker");
+    kw_endclass = &IdentTable.get("endclass");
+    kw_endclocking = &IdentTable.get("endclocking");
+    kw_endfunction = &IdentTable.get("endfunction");
+    kw_endgenerate = &IdentTable.get("endgenerate");
+    kw_endgroup = &IdentTable.get("endgroup");
+    kw_endinterface = &IdentTable.get("endinterface");
+    kw_endmodule = &IdentTable.get("endmodule");
+    kw_endpackage = &IdentTable.get("endpackage");
+    kw_endprimitive = &IdentTable.get("endprimitive");
+    kw_endprogram = &IdentTable.get("endprogram");
+    kw_endproperty = &IdentTable.get("endproperty");
+    kw_endsequence = &IdentTable.get("endsequence");
+    kw_endspecify = &IdentTable.get("endspecify");
+    kw_endtable = &IdentTable.get("endtable");
+    kw_endtask = &IdentTable.get("endtask");
+    kw_forever = &IdentTable.get("forever");
+    kw_fork = &IdentTable.get("fork");
+    kw_generate = &IdentTable.get("generate");
+    kw_highz0 = &IdentTable.get("highz0");
+    kw_highz1 = &IdentTable.get("highz1");
+    kw_iff = &IdentTable.get("iff");
+    kw_ifnone = &IdentTable.get("ifnone");
+    kw_ignore_bins = &IdentTable.get("ignore_bins");
+    kw_illegal_bins = &IdentTable.get("illegal_bins");
+    kw_initial = &IdentTable.get("initial");
+    kw_inout = &IdentTable.get("inout");
+    kw_input = &IdentTable.get("input");
+    kw_inside = &IdentTable.get("inside");
+    kw_interconnect = &IdentTable.get("interconnect");
+    kw_intersect = &IdentTable.get("intersect");
+    kw_join = &IdentTable.get("join");
+    kw_join_any = &IdentTable.get("join_any");
+    kw_join_none = &IdentTable.get("join_none");
+    kw_large = &IdentTable.get("large");
+    kw_local = &IdentTable.get("local");
+    kw_localparam = &IdentTable.get("localparam");
+    kw_macromodule = &IdentTable.get("macromodule");
+    kw_matches = &IdentTable.get("matches");
+    kw_medium = &IdentTable.get("medium");
+    kw_output = &IdentTable.get("output");
+    kw_packed = &IdentTable.get("packed");
+    kw_parameter = &IdentTable.get("parameter");
+    kw_primitive = &IdentTable.get("primitive");
+    kw_priority = &IdentTable.get("priority");
+    kw_program = &IdentTable.get("program");
+    kw_property = &IdentTable.get("property");
+    kw_pull0 = &IdentTable.get("pull0");
+    kw_pull1 = &IdentTable.get("pull1");
+    kw_pure = &IdentTable.get("pure");
+    kw_rand = &IdentTable.get("rand");
+    kw_randc = &IdentTable.get("randc");
+    kw_randcase = &IdentTable.get("randcase");
+    kw_randsequence = &IdentTable.get("randsequence");
+    kw_repeat = &IdentTable.get("repeat");
+    kw_sample = &IdentTable.get("sample");
+    kw_scalared = &IdentTable.get("scalared");
+    kw_sequence = &IdentTable.get("sequence");
+    kw_small = &IdentTable.get("small");
+    kw_soft = &IdentTable.get("soft");
+    kw_solve = &IdentTable.get("solve");
+    kw_specify = &IdentTable.get("specify");
+    kw_specparam = &IdentTable.get("specparam");
+    kw_strong0 = &IdentTable.get("strong0");
+    kw_strong1 = &IdentTable.get("strong1");
+    kw_supply0 = &IdentTable.get("supply0");
+    kw_supply1 = &IdentTable.get("supply1");
+    kw_table = &IdentTable.get("table");
+    kw_tagged = &IdentTable.get("tagged");
+    kw_task = &IdentTable.get("task");
+    kw_tri = &IdentTable.get("tri");
+    kw_tri0 = &IdentTable.get("tri0");
+    kw_tri1 = &IdentTable.get("tri1");
+    kw_triand = &IdentTable.get("triand");
+    kw_trior = &IdentTable.get("trior");
+    kw_trireg = &IdentTable.get("trireg");
+    kw_unique = &IdentTable.get("unique");
+    kw_unique0 = &IdentTable.get("unique0");
+    kw_uwire = &IdentTable.get("uwire");
+    kw_vectored = &IdentTable.get("vectored");
+    kw_wand = &IdentTable.get("wand");
+    kw_weak0 = &IdentTable.get("weak0");
+    kw_weak1 = &IdentTable.get("weak1");
+    kw_wildcard = &IdentTable.get("wildcard");
+    kw_wire = &IdentTable.get("wire");
+    kw_with = &IdentTable.get("with");
+    kw_wor = &IdentTable.get("wor");
+
     // Keep this at the end of the constructor to make sure everything here
     // is
     // already initialized.
     JsExtraKeywords = std::unordered_set<IdentifierInfo *>(
         {kw_as, kw_async, kw_await, kw_declare, kw_finally, kw_from,
          kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_override,
          kw_readonly, kw_set, kw_type, kw_typeof, kw_var, kw_yield,
          // Keywords from the Java section.
          kw_abstract, kw_extends, kw_implements, kw_instanceof, kw_interface});
 
     CSharpExtraKeywords = std::unordered_set<IdentifierInfo *>(
         {kw_base, kw_byte, kw_checked, kw_decimal, kw_delegate, kw_event,
          kw_fixed, kw_foreach, kw_implicit, kw_in, kw_init, kw_interface,
          kw_internal, kw_is, kw_lock, kw_null, kw_object, kw_out, kw_override,
          kw_params, kw_readonly, kw_ref, kw_string, kw_stackalloc, kw_sbyte,
          kw_sealed, kw_uint, kw_ulong, kw_unchecked, kw_unsafe, kw_ushort,
          kw_when, kw_where,
          // Keywords from the JavaScript section.
          kw_as, kw_async, kw_await, kw_declare, kw_finally, kw_from,
          kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_readonly,
          kw_set, kw_type, kw_typeof, kw_var, kw_yield,
          // Keywords from the Java section.
          kw_abstract, kw_extends, kw_implements, kw_instanceof, kw_interface});
+
+    // Some keywords are not included here because they don't need special
+    // treatment like `showcancelled` or they should be treated as identifiers
+    // like `int` and `logic`.
+    VerilogExtraKeywords = std::unordered_set<IdentifierInfo *>(
+        {kw_always,       kw_always_comb,  kw_always_ff,    kw_always_latch,
+         kw_assert,       kw_assign,       kw_assume,       kw_automatic,
+         kw_before,       kw_begin,        kw_bins,         kw_binsof,
+         kw_casex,        kw_casez,        kw_celldefine,   kw_checker,
+         kw_clocking,     kw_constraint,   kw_cover,        kw_covergroup,
+         kw_coverpoint,   kw_disable,      kw_dist,         kw_end,
+         kw_endcase,      kw_endchecker,   kw_endclass,     kw_endclocking,
+         kw_endfunction,  kw_endgenerate,  kw_endgroup,     kw_endinterface,
+         kw_endmodule,    kw_endpackage,   kw_endprimitive, kw_endprogram,
+         kw_endproperty,  kw_endsequence,  kw_endspecify,   kw_endtable,
+         kw_endtask,      kw_extends,      kw_final,        kw_foreach,
+         kw_forever,      kw_fork,         kw_function,     kw_generate,
+         kw_highz0,       kw_highz1,       kw_iff,          kw_ifnone,
+         kw_ignore_bins,  kw_illegal_bins, kw_implements,   kw_import,
+         kw_initial,      kw_inout,        kw_input,        kw_inside,
+         kw_interconnect, kw_interface,    kw_intersect,    kw_join,
+         kw_join_any,     kw_join_none,    kw_large,        kw_let,
+         kw_local,        kw_localparam,   kw_macromodule,  kw_matches,
+         kw_medium,       kw_output,       kw_package,      kw_packed,
+         kw_parameter,    kw_primitive,    kw_priority,     kw_program,
+         kw_property,     kw_pull0,        kw_pull1,        kw_pure,
+         kw_rand,         kw_randc,        kw_randcase,     kw_randsequence,
+         kw_ref,          kw_repeat,       kw_sample,       kw_scalared,
+         kw_sequence,     kw_small,        kw_soft,         kw_solve,
+         kw_specify,      kw_specparam,    kw_strong0,      kw_strong1,
+         kw_supply0,      kw_supply1,      kw_table,        kw_tagged,
+         kw_task,         kw_tri,          kw_tri0,         kw_tri1,
+         kw_triand,       kw_trior,        kw_trireg,       kw_unique,
+         kw_unique0,      kw_uwire,        kw_var,          kw_vectored,
+         kw_wand,         kw_weak0,        kw_weak1,        kw_wildcard,
+         kw_wire,         kw_with,         kw_wor});
   }
 
   // Context sensitive keywords.
   IdentifierInfo *kw_final;
   IdentifierInfo *kw_override;
   IdentifierInfo *kw_in;
   IdentifierInfo *kw_of;
   IdentifierInfo *kw_CF_CLOSED_ENUM;
struct AdditionalKeywords {
   IdentifierInfo *kw_uint;
   IdentifierInfo *kw_ulong;
   IdentifierInfo *kw_unchecked;
   IdentifierInfo *kw_unsafe;
   IdentifierInfo *kw_ushort;
   IdentifierInfo *kw_when;
   IdentifierInfo *kw_where;
 
+  // Verilog keywords
+  IdentifierInfo *kw_always;
+  IdentifierInfo *kw_always_comb;
+  IdentifierInfo *kw_always_ff;
+  IdentifierInfo *kw_always_latch;
+  IdentifierInfo *kw_assign;
+  IdentifierInfo *kw_assume;
+  IdentifierInfo *kw_automatic;
+  IdentifierInfo *kw_before;
+  IdentifierInfo *kw_begin;
+  IdentifierInfo *kw_bins;
+  IdentifierInfo *kw_binsof;
+  IdentifierInfo *kw_casex;
+  IdentifierInfo *kw_casez;
+  IdentifierInfo *kw_celldefine;
+  IdentifierInfo *kw_checker;
+  IdentifierInfo *kw_clocking;
+  IdentifierInfo *kw_constraint;
+  IdentifierInfo *kw_cover;
+  IdentifierInfo *kw_covergroup;
+  IdentifierInfo *kw_coverpoint;
+  IdentifierInfo *kw_disable;
+  IdentifierInfo *kw_dist;
+  IdentifierInfo *kw_end;
+  IdentifierInfo *kw_endcase;
+  IdentifierInfo *kw_endchecker;
+  IdentifierInfo *kw_endclass;
+  IdentifierInfo *kw_endclocking;
+  IdentifierInfo *kw_endfunction;
+  IdentifierInfo *kw_endgenerate;
+  IdentifierInfo *kw_endgroup;
+  IdentifierInfo *kw_endinterface;
+  IdentifierInfo *kw_endmodule;
+  IdentifierInfo *kw_endpackage;
+  IdentifierInfo *kw_endprimitive;
+  IdentifierInfo *kw_endprogram;
+  IdentifierInfo *kw_endproperty;
+  IdentifierInfo *kw_endsequence;
+  IdentifierInfo *kw_endspecify;
+  IdentifierInfo *kw_endtable;
+  IdentifierInfo *kw_endtask;
+  IdentifierInfo *kw_forever;
+  IdentifierInfo *kw_fork;
+  IdentifierInfo *kw_generate;
+  IdentifierInfo *kw_highz0;
+  IdentifierInfo *kw_highz1;
+  IdentifierInfo *kw_iff;
+  IdentifierInfo *kw_ifnone;
+  IdentifierInfo *kw_ignore_bins;
+  IdentifierInfo *kw_illegal_bins;
+  IdentifierInfo *kw_initial;
+  IdentifierInfo *kw_inout;
+  IdentifierInfo *kw_input;
+  IdentifierInfo *kw_inside;
+  IdentifierInfo *kw_interconnect;
+  IdentifierInfo *kw_intersect;
+  IdentifierInfo *kw_join;
+  IdentifierInfo *kw_join_any;
+  IdentifierInfo *kw_join_none;
+  IdentifierInfo *kw_large;
+  IdentifierInfo *kw_local;
+  IdentifierInfo *kw_localparam;
+  IdentifierInfo *kw_macromodule;
+  IdentifierInfo *kw_matches;
+  IdentifierInfo *kw_medium;
+  IdentifierInfo *kw_output;
+  IdentifierInfo *kw_packed;
+  IdentifierInfo *kw_parameter;
+  IdentifierInfo *kw_primitive;
+  IdentifierInfo *kw_priority;
+  IdentifierInfo *kw_program;
+  IdentifierInfo *kw_property;
+  IdentifierInfo *kw_pull0;
+  IdentifierInfo *kw_pull1;
+  IdentifierInfo *kw_pure;
+  IdentifierInfo *kw_rand;
+  IdentifierInfo *kw_randc;
+  IdentifierInfo *kw_randcase;
+  IdentifierInfo *kw_randsequence;
+  IdentifierInfo *kw_repeat;
+  IdentifierInfo *kw_sample;
+  IdentifierInfo *kw_scalared;
+  IdentifierInfo *kw_sequence;
+  IdentifierInfo *kw_small;
+  IdentifierInfo *kw_soft;
+  IdentifierInfo *kw_solve;
+  IdentifierInfo *kw_specify;
+  IdentifierInfo *kw_specparam;
+  IdentifierInfo *kw_strong0;
+  IdentifierInfo *kw_strong1;
+  IdentifierInfo *kw_supply0;
+  IdentifierInfo *kw_supply1;
+  IdentifierInfo *kw_table;
+  IdentifierInfo *kw_tagged;
+  IdentifierInfo *kw_task;
+  IdentifierInfo *kw_tri;
+  IdentifierInfo *kw_tri0;
+  IdentifierInfo *kw_tri1;
+  IdentifierInfo *kw_triand;
+  IdentifierInfo *kw_trior;
+  IdentifierInfo *kw_trireg;
+  IdentifierInfo *kw_unique;
+  IdentifierInfo *kw_unique0;
+  IdentifierInfo *kw_uwire;
+  IdentifierInfo *kw_vectored;
+  IdentifierInfo *kw_wand;
+  IdentifierInfo *kw_weak0;
+  IdentifierInfo *kw_weak1;
+  IdentifierInfo *kw_wildcard;
+  IdentifierInfo *kw_wire;
+  IdentifierInfo *kw_with;
+  IdentifierInfo *kw_wor;
+
   /// Returns \c true if \p Tok is a true JavaScript identifier, returns
   /// \c false if it is a keyword or a pseudo keyword.
   /// If \c AcceptIdentifierName is true, returns true not only for keywords,
   // but also for IdentifierName tokens (aka pseudo-keywords), such as
   // ``yield``.
   bool IsJavaScriptIdentifier(const FormatToken &Tok,
                               bool AcceptIdentifierName = true) const {
     // Based on the list of JavaScript & TypeScript keywords here:
case tok::kw_while:
       return true;
     default:
       return Tok.is(tok::identifier) &&
              CSharpExtraKeywords.find(Tok.Tok.getIdentifierInfo()) ==
                  CSharpExtraKeywords.end();
     }
   }
 
+  bool isVerilogIdentifier(const FormatToken &Tok) const {
+    switch (Tok.Tok.getKind()) {
+    case tok::kw_case:
+    case tok::kw_class:
+    case tok::kw_const:
+    case tok::kw_continue:
+    case tok::kw_default:
+    case tok::kw_do:
+    case tok::kw_extern:
+    case tok::kw_else:
+    case tok::kw_enum:
+    case tok::kw_for:
+    case tok::kw_if:
+    case tok::kw_restrict:
+    case tok::kw_signed:
+    case tok::kw_static:
+    case tok::kw_struct:
+    case tok::kw_typedef:
+    case tok::kw_union:
+    case tok::kw_unsigned:
+    case tok::kw_virtual:
+    case tok::kw_while:
+      return false;
+    case tok::identifier:
+      return VerilogExtraKeywords.find(Tok.Tok.getIdentifierInfo()) ==
+             VerilogExtraKeywords.end();
+    default:
+      // getIdentifierInfo returns non-null for both identifiers and keywords.
+      return Tok.Tok.getIdentifierInfo() != nullptr;
+    }
+  }
+
+  /// Returns whether \p Tok is a Verilog keyword that opens a block.
+  bool isVerilogBegin(const FormatToken &Tok) const {
+    // `table` is not included since it needs to be treated specially.
+    return !Tok.endsSequence(kw_fork, kw_disable) &&
+           Tok.isOneOf(kw_begin, kw_fork, kw_generate, kw_specify);
+  }
+
+  /// Returns whether \p Tok is a Verilog keyword that closes a block.
+  bool isVerilogEnd(const FormatToken &Tok) const {
+    return !Tok.endsSequence(kw_join, kw_rand) &&
+           Tok.isOneOf(TT_MacroBlockEnd, kw_end, kw_endcase, kw_endclass,
+                       kw_endclocking, kw_endchecker, kw_endfunction,
+                       kw_endgenerate, kw_endgroup, kw_endinterface,
+                       kw_endmodule, kw_endpackage, kw_endprimitive,
+                       kw_endprogram, kw_endproperty, kw_endsequence,
+                       kw_endspecify, kw_endtable, kw_endtask, kw_join_any,
+                       kw_join_none);
+  }
+
+  /// Whether the token begins a block.
+  bool isBlockBegin(const FormatToken &Tok, const FormatStyle &Style) const {
+    return Tok.is(TT_MacroBlockBegin) ||
+           (Style.isVerilog() ? isVerilogBegin(Tok) : Tok.is(tok::l_brace));
+  }
+
 private:
   /// The JavaScript keywords beyond the C++ keyword set.
   std::unordered_set<IdentifierInfo *> JsExtraKeywords;
 
   /// The C# keywords beyond the C++ keyword set
   std::unordered_set<IdentifierInfo *> CSharpExtraKeywords;
+
+  /// The Verilog keywords beyond the C++ keyword set.
+  std::unordered_set<IdentifierInfo *> VerilogExtraKeywords;
 };
 
 } // namespace format
 } // namespace clang
 
 #endif

clang/lib/Format/UnwrappedLineParser.cpp

bool UnwrappedLineParser::mightFitOnOneLine(
 
   return Line.Level * Style.IndentWidth + Length <= ColumnLimit;
 }
 
 FormatToken *UnwrappedLineParser::parseBlock(
     bool MustBeDeclaration, unsigned AddLevels, bool MunchSemi, bool KeepBraces,
     IfStmtKind *IfKind, bool UnindentWhitesmithsBraces,
     bool CanContainBracedList, TokenType NextLBracesType) {
-  assert(FormatTok->isOneOf(tok::l_brace, TT_MacroBlockBegin) &&
+  auto HandleVerilogBlockLabel = [this]() {
+    // ":" name
+    if (Style.isVerilog() && FormatTok->is(tok::colon)) {
+      nextToken();
+      if (Keywords.isVerilogIdentifier(*FormatTok))
+        nextToken();
+    }
+  };
+
+  assert((FormatTok->isOneOf(tok::l_brace, TT_MacroBlockBegin) ||
+          (Style.isVerilog() && Keywords.isVerilogBegin(*FormatTok))) &&
          "'{' or macro block token expected");
   FormatToken *Tok = FormatTok;
   const bool FollowedByComment = Tokens->peekNextToken()->is(tok::comment);
   auto Index = CurrentLines->size();
   const bool MacroBlock = FormatTok->is(TT_MacroBlockBegin);
   FormatTok->setBlockKind(BK_Block);
 
   // For Whitesmiths mode, jump to the next level prior to skipping over the
   // braces.
   if (AddLevels > 0 && Style.BreakBeforeBraces == FormatStyle::BS_Whitesmiths)
     ++Line->Level;
 
   size_t PPStartHash = computePPHash();
 
   const unsigned InitialLevel = Line->Level;
   nextToken(/*LevelDifference=*/AddLevels);
+  HandleVerilogBlockLabel();
 
   // Bail out if there are too many levels. Otherwise, the stack might overflow.
   if (Line->Level > 300)
     return nullptr;
 
   if (MacroBlock && FormatTok->is(tok::l_paren))
     parseParens();
 
if (RemoveBraces()) {
     Tok->MatchingParen = FormatTok;
     FormatTok->MatchingParen = Tok;
   }
 
   size_t PPEndHash = computePPHash();
 
   // Munch the closing brace.
   nextToken(/*LevelDifference=*/-AddLevels);
+  HandleVerilogBlockLabel();
 
   if (MacroBlock && FormatTok->is(tok::l_paren))
     parseParens();
 
   if (FormatTok->is(tok::kw_noexcept)) {
     // A noexcept in a requires expression.
     nextToken();
   }
FormatToken *UnwrappedLineParser::parseIfThenElse(IfStmtKind *IfKind,
   handleAttributes();
 
   bool NeedsUnwrappedLine = false;
   keepAncestorBraces();
 
   FormatToken *IfLeftBrace = nullptr;
   IfStmtKind IfBlockKind = IfStmtKind::NotIf;
 
-  if (FormatTok->is(tok::l_brace)) {
+  if (Keywords.isBlockBegin(*FormatTok, Style)) {
     FormatTok->setFinalizedType(TT_ControlStatementLBrace);
     IfLeftBrace = FormatTok;
     CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false, /*AddLevels=*/1u,
                /*MunchSemi=*/true, KeepIfBraces, &IfBlockKind);
     if (Style.BraceWrapping.BeforeElse)
       addUnwrappedLine();
     else
FormatToken *UnwrappedLineParser::parseIfThenElse(IfStmtKind *IfKind,
 
   if (FormatTok->is(tok::kw_else)) {
     if (Style.RemoveBracesLLVM) {
       NestedTooDeep.back() = false;
       Kind = IfStmtKind::IfElse;
     }
     nextToken();
     handleAttributes();
-    if (FormatTok->is(tok::l_brace)) {
+    if (Keywords.isBlockBegin(*FormatTok, Style)) {
       const bool FollowedByIf = Tokens->peekNextToken()->is(tok::kw_if);
       FormatTok->setFinalizedType(TT_ElseLBrace);
       ElseLeftBrace = FormatTok;
       CompoundStatementIndenter Indenter(this, Style, Line->Level);
       IfStmtKind ElseBlockKind = IfStmtKind::NotIf;
       FormatToken *IfLBrace =
           parseBlock(/*MustBeDeclaration=*/false, /*AddLevels=*/1u,
                      /*MunchSemi=*/true, KeepElseBraces, &ElseBlockKind);
do {
     }
     nextToken();
   } while (!eof());
 }
 
 void UnwrappedLineParser::parseLoopBody(bool KeepBraces, bool WrapRightBrace) {
   keepAncestorBraces();
 
-  if (FormatTok->is(tok::l_brace)) {
+  if (Keywords.isBlockBegin(*FormatTok, Style)) {
     if (!KeepBraces)
       FormatTok->setFinalizedType(TT_ControlStatementLBrace);
     FormatToken *LeftBrace = FormatTok;
     CompoundStatementIndenter Indenter(this, Style, Line->Level);
     parseBlock(/*MustBeDeclaration=*/false, /*AddLevels=*/1u,
                /*MunchSemi=*/true, KeepBraces);
     if (!KeepBraces) {
       assert(!NestedTooDeep.empty());
void UnwrappedLineParser::nextToken(int LevelDifference) {
   flushComments(isOnNewLine(*FormatTok));
   pushToken(FormatTok);
   FormatToken *Previous = FormatTok;
   if (!Style.isJavaScript())
     readToken(LevelDifference);
   else
     readTokenWithJavaScriptASI();
   FormatTok->Previous = Previous;
+  if (Style.isVerilog()) {
+    // Blocks in Verilog can have `begin` and `end` instead of braces.  For
+    // keywords like `begin`, we can't treat them the same as left braces
+    // because some contexts require one of them.  For example structs use
+    // braces and if blocks use keywords, and a left brace can occur in an if
+    // statement, but it is not a block.  For keywords like `end`, we simply
+    // treat them the same as right braces.
+    if (Keywords.isVerilogEnd(*FormatTok))
+      FormatTok->Tok.setKind(tok::r_brace);
+  }
 }
 
 void UnwrappedLineParser::distributeComments(
     const SmallVectorImpl<FormatToken *> &Comments,
     const FormatToken *NextTok) {
   // Whether or not a line comment token continues a line is controlled by
   // the method continuesLineCommentSection, with the following caveat:
   //

clang/tools/clang-format/ClangFormat.cpp

FallbackStyle("fallback-style",
                            "Use -fallback-style=none to skip formatting."),
                   cl::init(clang::format::DefaultFallbackStyle),
                   cl::cat(ClangFormatCategory));
 
 static cl::opt<std::string> AssumeFileName(
     "assume-filename",
     cl::desc("Override filename used to determine the language.\n"
              "When reading from stdin, clang-format assumes this\n"
-             "filename to determine the language."),
+             "filename to determine the language.\n"
+             "Unrecognized filenames are treated as C++.\n"
+             "supported:\n"
+             "  CSharp: .cs\n"
+             "  Java: .java\n"
+             "  JavaScript: .mjs .js .ts\n"
+             "  Json: .json\n"
+             "  Objective-C: .m .mm\n"
+             "  Proto: .proto .protodevel\n"
+             "  TableGen: .td\n"
+             "  TextProto: .textpb .pb.txt .textproto .asciipb\n"
+             "  Verilog: .sv .svh .v .vh"),
     cl::init("<stdin>"), cl::cat(ClangFormatCategory));
 
 static cl::opt<bool> Inplace("i",
                              cl::desc("Inplace edit <file>s, if specified."),
                              cl::cat(ClangFormatCategory));
 
 static cl::opt<bool> OutputXML("output-replacements-xml",
                                cl::desc("Output replacements as XML."),

clang/unittests/Format/CMakeLists.txt

add_clang_unittest(FormatTests
   FormatTestJava.cpp
   FormatTestJson.cpp
   FormatTestObjC.cpp
   FormatTestProto.cpp
   FormatTestRawStrings.cpp
   FormatTestSelective.cpp
   FormatTestTableGen.cpp
   FormatTestTextProto.cpp
+  FormatTestVerilog.cpp
   MacroExpanderTest.cpp
   NamespaceEndCommentsFixerTest.cpp
   QualifierFixerTest.cpp
   SortImportsTestJS.cpp
   SortImportsTestJava.cpp
   SortIncludesTest.cpp
   UsingDeclarationsSorterTest.cpp
   TokenAnnotatorTest.cpp

clang/unittests/Format/FormatTestUtils.h

 #define LLVM_CLANG_UNITTESTS_FORMAT_FORMATTESTUTILS_H
 
 #include "llvm/ADT/StringRef.h"
 
 namespace clang {
 namespace format {
 namespace test {
 
-inline std::string messUp(llvm::StringRef Code) {
+// When HandleHash is false, preprocessor directives starting with hash will not
+// be on separate lines.  This is needed because Verilog uses hash for other
+// purposes.
+inline std::string messUp(llvm::StringRef Code, bool HandleHash = true) {
   std::string MessedUp(Code.str());
   bool InComment = false;
   bool InPreprocessorDirective = false;
   bool JustReplacedNewline = false;
   for (unsigned i = 0, e = MessedUp.size() - 1; i != e; ++i) {
     if (MessedUp[i] == '/' && MessedUp[i + 1] == '/') {
       if (JustReplacedNewline)
         MessedUp[i - 1] = '\n';
       InComment = true;
-    } else if (MessedUp[i] == '#' &&
+    } else if (HandleHash && MessedUp[i] == '#' &&
                (JustReplacedNewline || i == 0 || MessedUp[i - 1] == '\n')) {
       if (i != 0)
         MessedUp[i - 1] = '\n';
       InPreprocessorDirective = true;
     } else if (MessedUp[i] == '\\' && MessedUp[i + 1] == '\n') {
       MessedUp[i] = ' ';
       MessedUp[i + 1] = ' ';
     } else if (MessedUp[i] == '\n') {

clang/unittests/Format/FormatTestVerilog.cpp

+//===- unittest/Format/FormatTestVerilog.cpp ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "FormatTestUtils.h"
+#include "clang/Format/Format.h"
+#include "llvm/Support/Debug.h"
+#include "gtest/gtest.h"
+
+#define DEBUG_TYPE "format-test"
+
+namespace clang {
+namespace format {
+
+class FormatTestVerilog : public ::testing::Test {
+protected:
+  static std::string format(llvm::StringRef Code, unsigned Offset,
+                            unsigned Length, const FormatStyle &Style) {
+    LLVM_DEBUG(llvm::errs() << "---\n");
+    LLVM_DEBUG(llvm::errs() << Code << "\n\n");
+    std::vector<tooling::Range> Ranges(1, tooling::Range(Offset, Length));
+    tooling::Replacements Replaces = reformat(Style, Code, Ranges);
+    auto Result = applyAllReplacements(Code, Replaces);
+    EXPECT_TRUE(static_cast<bool>(Result));
+    LLVM_DEBUG(llvm::errs() << "\n" << *Result << "\n\n");
+    return *Result;
+  }
+
+  static std::string format(llvm::StringRef Code, const FormatStyle &Style) {
+    return format(Code, 0, Code.size(), Style);
+  }
+
+  static void verifyFormat(
+      llvm::StringRef Code,
+      const FormatStyle &Style = getLLVMStyle(FormatStyle::LK_Verilog)) {
+    EXPECT_EQ(Code.str(), format(Code, Style)) << "Expected code is not stable";
+    EXPECT_EQ(Code.str(),
+              format(test::messUp(Code, /*HandleHash=*/false), Style));
+  }
+};
+
+TEST_F(FormatTestVerilog, If) {
+  verifyFormat("if (x)\n"
+               "  x = x;");
+  verifyFormat("if (x)\n"
+               "  x = x;\n"
+               "x = x;");
+
+  // Test else
+  verifyFormat("if (x)\n"
+               "  x = x;\n"
+               "else if (x)\n"
+               "  x = x;\n"
+               "else\n"
+               "  x = x;");
+  verifyFormat("if (x) begin\n"
+               "  x = x;\n"
+               "end else if (x) begin\n"
+               "  x = x;\n"
+               "end else begin\n"
+               "  x = x;\n"
+               "end");
+  verifyFormat("if (x) begin : x\n"
+               "  x = x;\n"
+               "end : x else if (x) begin : x\n"
+               "  x = x;\n"
+               "end : x else begin : x\n"
+               "  x = x;\n"
+               "end : x");
+
+  // Test block keywords.
+  verifyFormat("if (x) begin\n"
+               "  x = x;\n"
+               "end");
+  verifyFormat("if (x) begin : x\n"
+               "  x = x;\n"
+               "end : x");
+  verifyFormat("if (x) begin\n"
+               "  x = x;\n"
+               "  x = x;\n"
+               "end");
+  verifyFormat("disable fork;\n"
+               "x = x;");
+  verifyFormat("rand join x x;\n"
+               "x = x;");
+  verifyFormat("if (x) fork\n"
+               "  x = x;\n"
+               "join");
+  verifyFormat("if (x) fork\n"
+               "  x = x;\n"
+               "join_any");
+  verifyFormat("if (x) fork\n"
+               "  x = x;\n"
+               "join_none");
+  verifyFormat("if (x) generate\n"
+               "  x = x;\n"
+               "endgenerate");
+  verifyFormat("if (x) generate : x\n"
+               "  x = x;\n"
+               "endgenerate : x");
+
+  // Test that concatenation braces don't get regarded as blocks.
+  verifyFormat("if (x)\n"
+               "  {x} = x;");
+  verifyFormat("if (x)\n"
+               "  x = {x};");
+  verifyFormat("if (x)\n"
+               "  x = {x};\n"
+               "else\n"
+               "  {x} = {x};");
+}
+
+} // namespace format
+} // end namespace clang